PUEBLO, Colo. — Zac Grant never let his truck run close to empty. Colorado’s weather was too unpredictable for that, and lately, the cost of fuel had been, too. In the weeks since the United States had attacked Iran, the price for a gallon had shot up nearly 35 percent in Colorado, a hike that far outpaced the national average, and one the state hadn’t seen in at least a quarter century.